1. Field of the Invention
The present invention relates to the field of plug and socket, and in particular to an improved fastening device of a plug-socket combination, in which a fastening plate is integrally formed with a plastic pawl through injection molding so as to provide a large engagement area, have an enhanced strength, and be not easily separated.
2. The Related Arts
One of the most influencing events for an industrial processing machine is unexpected interruption of power supply. The interruption of power supply may result in lowering of product yield rate and also affect the schedule of the processing operation and what is even worse is causing loss of the original processing or operation parameters. Further, power failure or interruption of power supply may lead to severe loss and damage. Conventional power plugs and sockets are often connected through plugging the blades of a plug into the slots of a socket to establish electrical connection. However, such a simple way of connection may cause ready separation of the blades of the plug from the slots of the socket due to for example stretching or pulling of the electrical cables to which the plug and the socket are mount or pulling of the plug and socket themselves. The consequence of such separation is the interruption of power supply.
To handle such a problem, as shown in FIG. 1, a fastening device of a plug-socket combination was proposed by the present inventor, including a plug structure 1 and a socket structure 2, wherein the socket structure 2 has a side wall, in which a slot 3, which is in a form for receiving a plate, is formed. An open recess 4, which faces outwards, is formed in the side wall to be at a lower end of the plate receiving slot 3. A fastening plate 5 has a lower end on which a spring plate 6 that extends upward in a slanting and outward-diverging manner. When the fastening plate 5 is inserted into the plate-receiving slot 3, the spring plate 6 is allowed to expand outward to engage and thus be positioned against a lower edge of the open recess 4. An elastic pawl 7 is formed on a free end of the fastening plate 5 so that when blades of the plug structure 1 are plugged into slots of the socket structure 2, the plug structure that comprises a positioning cavity 8 is allowed to smoothly pass through the elastic pawl 7 to have the positioning cavity 8 aligning with the elastic pawl 7 whereby the elastic pawl 7 may be driven by the elasticity to get into and thus fix the positioning cavity 8 so as to prevent the plug structure 1 from separating from the socket structure 2 and securely maintaining the connection between the plug structure 1 and the socket structure 2, without being separated due to being pulled by external forces, to ensure normal power supply therethrough. However, although it is possible to prevent separation caused by pulling or stretching, the fastening plate 5 is made of metal so that the fastening plate 5 and the pawl 7 have a thickness that is small, providing the elastic pawl 7 with insufficient strength. Thus, further improvements are necessary.
Thus, the present invention aims to provide a novel structure that overcomes the above-discussed problems and issues.